Electromagnetic relay



Oct. 18, 1932. J. ERICKSON I ELECTROMAGNETIC RELAY Filed May 18, 1951Inuenlczr- Jahn Erickson value.

Patented oct.. 181932 UNITED STATES llaTlaziaT oFFlci;

JOHN ERICKSON, OF CHICAGO, ILLINOIS, ASSIGNOB, Bf MESNE ASSIGNIEN'TS, T0

ASSOCIATED ELECTRIC LABORATORIES, 'INCWOF CHICAGO, ILLINOIS, A CORPORA-TION F DELAWARE ELECTROLIAGNETIC RELAY Application led lay 18, 1931.Serial No.`538,05 8.

This invention relates-in general to electromagnetic relays, but moreparticularly to relays which are operated by alternating current, andthe principal `obj ect of the invention is to design a new and improvedalternating current relay, which will be extremely sensitive andeiicient in operation, will control a larger number of contact springswith better contact ressure between the springs, and besimple 1nconstructionl and economical to' manufacture.

In alternating current relays, when the relay winding'is energized thearmature has a tendency to chatter or hum due to the current in the coilpassino' through zero `potential This may effect the contact springscontrolled by the armature and result in un- .desired operations. To'a`void this .chattering of the armature, vvarious means have beencdevised to provide a secondary orholding flux in the magnetic circuitof the relay whlch is out of phase with the primar or main flux of therelay soas to maintain t e armature in its attracted position at thetime that the main f flux ceases to ilow due to the cycles ofalternating current being at zer'o potential. This l is commonly knownas pole shading and lone method of accomplishing this is to rovide acopper ring or short-circuited win ing on the armature end of the core.

It is an object of the invention to design a relay having new .andimproved meansv for providing a displacement ofthe main lux flowingthrough the relay, and in accordance with this object a particularfeature of the" invention resides in providing a novel shading coilwhich in general takes the form of a short-circuited winding or ring ofelectric current conducting material enclosing a portion of a pole faceor core of the relay.

A particular feature of the invention resides in providin a plurality ofwashers made of copper w ich perfornrthe function ofYrint-roducing adisplacement of the main flux flowing through the core of the relay, and

depending upon the number of washers assembled together theamount ofthis displacement of the iux may be adjustable.

Another feature of the invention is directed to a novel mounting lateand its arrangement for supporting t e contact spring sets, thearmature, and the relay as a unlt.

laminations of the. magnetic structure of the relay and at the same timesecurely supporting the armature and spring mounting plates to thestructure. l

The above objects and features and others will be apparent from thefollowing detailed description, which, together with the-sheet ofdrawings, illustrates a preferred embodiment of the invention.

In the accompanying drawing, Fig. 1 illustrates in elevation a relayembod ing the invention; Fig. 2 is a rear view o'gthe relsy taken fromthe left-hand side of Fig. 1 ig. 3 is a perspective view showing onlythe laminated core and the mounting plates, the other parts of the relaybeing removed; F lgl. 4is a top view of the relay; while Fi 5 s ows aperspective of a pair of pole shaders or short-circuiting copper rings.`

Referring to the drawing, the relay lcomprises the coil or winding 5wound between An additional feature of the invention rei sides in themeans lfor holding together the a pair of insulated spool-heads 6 oneach end,

as seen inA Fi v1.- Al-preferred method of holding the wlnding of thecoil is to provide an insulated or bakelite spool with which apair oflegs 7 and 8 )oined together at one a end. This magnetic member 1spreferably constructed of silicon iron and consists of af plurality ofthin pieces of laminations bound together to form"l a unitary structure.The coil wound upon the spool 6, is placed` over the leg 7 of themagnetic member and in `this way itserves as a core for the coil.

A pair of substantially Z-shaped non-magnetic supporting plates 9 and 10are mounted on each side of the leg 8 of the magnetic member. Themounting plate 9 he a a turned over extension 11 for lsupporting one endof the armature While at the bottom of j the plate 9 a turned overportion 13 servesas a means for supporting the complete relay on asuitable base. The plate also has a turned up ear portion 12 forsupportingthe armature, and at the bottom asimilar portion such as 13 onplate 9 for supporting the relay. The plates 9 and 10 are secured to thelegs 7 and 8 at the bottom of the coil by means of a pair of rivetsltextending from each 4of the extensions 13 directly through thelaminated pieces of` the core to .the opposite side where they areriveted together. At the opposite top end of'each ot the plates 9 and 10a pair yof rivets 16 are provided which extend from extension 11 of theplate 9 through the laminat-ions of the leg 8 to the projection 12 wherethe are Jriveted together. Additional rivetsj15 on the leg 7 of themag'- netic member are provided in order to secure the laminationstogether on the leg 7.

With the foregoing structure it'is seen that the laminations andtheplates 9 and 10 are secured together by the rivets 14 on the bottom sideof the U-Shaped magnetic member,`

and at the top `by the rivets 16`to form a solid unitary structure.

j The leg 7 of the core is provided at its-end with a'pair ofprojections'or pole-pieces 17 and 18 separated by a slot so that one ormore copper rings 19 and 20 may be-placed on lthe leg 7 surrounding thisprojection 18. In order to securely hold the copper rings 19 and 20 ontothe leg 7, the last two laminations on each side of the leg 7 are bentlover on' the top vof the ring 19. This prevents dislodgment of therings and at the same time securely holds the coil 5 onto the leg 7.vThe lcopper rings 19 and 2O then lie directly upon the top edge of theinsulated spool-heads 6.

The armature -is provided at its vend with a brass residual pin 26 whichstrikes against the end of pole-piece. 18 to prevent sticking of thearmature 26 on the core when the coil is deenergized. The armaturev25 isypivoted by pin 27 to the supporting member 28 which in yturn is securedby screws 29 and 30 in the extensions 11 and 12 of the supporting plates9 and 10.v The screws 29 and 30, when loosened permit the supportingmember 28 to slidevup or down in the slots 31 and thereby adjust thearmature stroke -with res ect to the ends of the pole pieces t' 17 andThe armature 25 is provided on each side with contact controlling arms32v Aposition of the armature. The contact spring sets 35 in addition tosuitable soldering *tags for coil5 are secured by screws 37 threadedinto the sides of mounting plates 9 and 10. In order to support therelay as a unit on a suitable mounting plate, the screw holes 21 on theplates 9 and 10 are provided.

It will be seen that with the foregoing construction ofrelay, when thewinding of coil 5 is energized by a suitable source of alternatingcurrent, a magnetic Hux is generated for operating the armature 25 whichextends over apath including the laminated core legs 7 and 8, armature25, and the pole-pieces 17 and 18 at the end of leg 7 This constitutesthe main lux which flows through the relay at each. cycle of thealternatingl current. This main lux will induce a current flow into thecopper rings 19 and 20 which lags or is the copper rings 19 and 20 willcause a holding flux tofollow a path extending from pole-piece 17through armature 25, back over pole-piece 18 and across the 4end of leg7 to pole-piece 17 again. 'llhis holding flux is of sufficient strengthto maintain the armature 25 in its attracted position between each cycleof the alternating current. It is therefore seen that at zero currentvalue through the c oil the holding iiux generated due to the currentinduced in the copper rings 19 and 2O holds vthe armature against thetwo polepieces 17 and 18 of the core 7 to maintain it in v a stableposition, and prevent it from fluttering in synchronismwith the cyclesofaltrnating current,'so that the contact springs 35 will remain operatedas long as the alternating current is connected to the coil 5.

When the relay is required to be operated in a circuit which provides asource of alternating current of a low frequency a condition exists inwhich-it is diiiicult to maintain the armature in an attracted positionduring the interval that the current is passing through zero potentialvalue. This occurs due to the fact that as the current builds up in thecoil 5 in the first half of its cycle the armature is not immediatelyattracted but only when the -lux is strong enough'to pull it down uponthe pole-pieces 17 and-18. Similarly in this half cycle as the fluxdecays, the armature will retract before the flux has fully ceased toflow and .before the current is at zero potential value. `It istherefore seen that before the opposite cycle of current. creates a fluxinthe opposite direction anap- .ireciable time interval exists duringwhich the armature will not remain o erated at the lo w frequencies.6Toprovide or this an addltional number of copper washers or rings 19 and20 are placed on thepole-piece 18 in order to create a greater holdingflux out of phase with the main flux through the relay and maintain thearmature attracted vand* stable between each cycle of the alternatingcurrent.

In instances Where the relay is to be operated by alternating current ofhigh frequencies a lesser number of copper washers 19 and 20 arerequired because the interval between each cycle of alternating currentduring which the armature is held attracted isl not as long as onlowfrequencies. l For all ordinary. purposes on frequencies .such asused in the telephone arta pair of copper `washers is all that isrequired.

p It is 'desired in certain instances that a greater number of springcombinations such as be operated by the karmature vfrom that shown. Whenthis occurs it will be appreciated that upon o eration of the contactsprin sets 35 consi erabletension will be store inthe armature springsso that when subsequently the current 'through coil 5 passes throughzero potential value it will require considerable lforce to maintain thearmature in its attracted position. In order vto induce a'greater flowof flux. in the holding magnetic circuit for holdingthe armatureattracted in this instance, additional copper rings or washers, such as19 and 20 may be piled up on the pole-piece 18 in order to create alarger amount'of ux from the main flux flowing through the magneticcircuit.

Similarly when a smaller set of spring combinations are used on therelay a less number of copper rings may be provided. This provides aconvenient method of adjusting the lag in the armature when desired.

Due to the fact that the magnetic circuit is completed over thelaminated U-shaped member which is made of silicon iron, a veryeilicient magnetic A circuit is provided thatis free of any retardingeddy currents, provides an efficient ath for the flux to How and also bepowerfu enough to operate the armature 25 to control a large number ofcontact spring sets.

hile only one embodiment of the invention has been shown and described,it is not desired to be limited to the exact arrange- .ment shown anddescribed butalso those modifications that may fall Within the spiritporting the armature of the relay in operative relation to the end ofsaid first leg, means on the other end of said supporting members formounting the relay as a unit, means on each of said suporting membersfor mounting a set of contact springs controlled by the armature, andmeans on said supportingmembers for adjusting the movement of thearmature against the first leg of the relay. l

2. In an electromagnetic relay, a U-shaped laminated magnetic structurehavinga winding on one leg,a` non-magnetic supporting plate on each sideof the other leg of the magnetic structure, means on opposite ends of.said supporting plate for securing the supporting plates and thelaminations of the magnetic structure together, means on one end of saidsupporting plates for securing the armature of the relay in operativerelat-ion to the other leg of the magnetic structure, means on the otherend of said supporting plates for mounting said relay, means between theends of said supporting plates for mounting a set of contact springscontrolled by the armature, and means on said supporting plates foradjusting the movement of said armature against the Winding leg of themagnetic structure.

3. In an alternating current relay, a U- shaped magnetic structurehaving a Winding on one leg, separate non-magnetic supporting plates oneach side of the other leg, means on one end of said supporting platesfor connecting them togethei` across the leg of the magnetic structureto form a support for the armature of the relay so that it will be inoperative relation with the end of the other leg', means on each of theends of said supporting plates for securing them to the magneticstructure, and means between the ends of each of the supporting plateslfor mounting a set ot Contact springs controlled by the armature. v 4.In an alternating current rela-y, a U- shaped magnetic structure havinga Winding on one leg, a pair of non-magnetic supporting plates onopposite sides of the other leg, means on one end'ot said supportingplates tor mounting the armature of the relay so that it is in operativerelation With the other leg of the structure, non-magnetic Washers onthe Winding leg arranged to provide a magnetic flux displayed in phaserelatively to the main fiux in the magnetic structure for maintainingthe armature attracted to prevent chattering thereof when the currentthrough the Winding passes through zero potential, and means on saidnon-magnetic supporting plates for mounting said relay as a unit andfor. securing sets of contactsprings thereon controlledby the armature.Y

5. In a-relay having a U-shaped magnetic structure, a Winding on one legthereof, a pair of non-magnetic supporting plates on v support for thearmature of the relay, said projections connected together and bridgingthe ma netic leg of the structure to form an adjnsta le support forvarying the movement ofthe armature against the other leg of thestructure, means on the other .end of said nonmagnetic supporting platesfor securing said relayto a mounting plate as a unit, means intermediatethe ends of the supporting plate for mounting sets of contact springscontrolled by the armature, and means on each end of said supportingplates for securing them to said magneticstructure.

6. An electromagnetic device having an armature and a magnetic structurecomprising two legs2 an 4energizing winding on onel leg, a mountlngmember on the other leg means on one end of said mounting member forsupporting the armature in operative'relation to sald first leg, meanson the opposite end of said mounting member for supporting the device asa unit, and means on said mounting memberforadjustin the movement ofJthe armature against the rst leg of the relay.

7. In an electromagnetic device having an armature, a magnetic structurehaving a pair of legs, an energizing winding on'one leg,

forming a ysupport for the armature and connected together across saidleg, means on said armature support for a justing the movement of thearmature against the winding leg, means on the other end of saidsupporting plates for supporting said device as a unit, and a pluralitof shadin coils supported around the endyof posite said armature and ontop of said windmg.

In witness.whereof, I hereunto subscribe my name this 14th dat?1 of May,A. D. 1931.

' @Y OHN ERICKSON.

mounting plates on each 'side ofy the other of said legs, means forvconnectingsaid plates together across said other leg to form a pivotfor the armature and so that it extends o po- 'site the end of saidfirst leg, shading coi on said first leg opposite said armature, andmeans on said mounting plates for supportn ing said device asv aunit.

8. In an electromagneticv device, a mag- `netic 'structure comprising apair of legs joined together at one end, an.- energizing wmdmg on one ofsaid legs, an armature-on the other of said legs and extending in operavtive relation to the first le supporting plates on said otherleg arrangeto pivot said armature and support said device as a nit, shadin coils onsaid first leg opposite the moving en 'of said armature, and means forholding said shading coils and the energizing winding together on saidfirst leg.

v9. In an electromagnetic device havinganv armature and a magneticstructure comprising two legs, an energizing winding. on one'of saidlegs, means for supporting the armature n the-other of said le tionto's'aid first leg, s ading coils on said in operative relai first leg,Aand means on said first leg for "l clam ing said shadin coils andenergizing win mg together 'on t e leg.

10, In an electromagnetic device havingan armature, a `ma etic`structure having two legs oined toget er on-one end, an energizing wining on V'one leg a pair ofhsupporting plates on opposite sides ofthe oter leg, pro- )ections on one end of said supporting plates the win ingleg opf

